Of course, being a mac user at home, after yesterday’s post on locking a windows machine I have been looking for a similar solution to automatically lock my mac when I step out. A similar setup as with btprox for Windows can be established easily by combining the power of an open-source tool called Proximity with a little AppleScript.
Proximity is a more generic solution that allows one to run an AppleScript when a Bluetooth device gets in or out of range. The generic solution was already described on Lifehacker and Macworld Hints. However, they both have a too generic solution where just getting in range with the paired device would unlock the computer, which is not exactly what I wanted. I use the following AppleScript instead, which only switches off iTunes if it is running (and does not start it when it is not) and locks the screen:
if application id "com.apple.iTunes" is running then
tell application id "com.apple.iTunes" to pauze
end if
activate application id "com.apple.ScreenSaver.Engine"
My Default settings for the screen saver to always require a password after 1 minute suffice for me and render the setup I need on my Mac OS X Lion machines.